Comparison of the effectiveness of saturation pulses in the heart at 3T
Comparison of the effectiveness of saturation pulses in the heart at 3T
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DOI：
10.1002/mrm.21423
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发表时间：
2008-01-01
影响因子：
3.3
通讯作者：
Axel, Leon
中科院分区：
文献类型：
--
作者：
Kim, Daniel;Gonen, Oded;Axel, Leon
3T心脏MRI为首次通过灌注MRI提供了一种提高对比噪声比(CNR)的手段。然而，心脏内的静磁场(B-0)和射频(B-1)场(B-1)的变化在3T时都比1.5T时相对较高。增加的场变化会降低通常用于磁化准备的单个矩形饱和脉冲的性能。T-1加权信号测量的精度取决于磁化饱和的均匀性。这项研究的目的是评估在3T时矩形、脉冲串和绝热复合(BIR-4)饱和脉冲在人体心脏中的相对有效性。在志愿者中，在标称饱和后，三种脉冲的左心室(LV)内的平均残余磁化强度不同(分别为0.13+/-0.06vs.0.03+/-0.02vs.0.03+/-0.01，P<；0.001)。在成对组内，矩形脉冲的平均剩余磁化强度显著高于脉冲串和BIR-4脉冲(P<；0.001)，但脉冲串和BIR-4脉冲之间没有差别。三种饱和脉冲在右室的表现均较左室差。
Cardiac MRI at 3T provides a means to increase the contrast-to-noise ratio (CNR) for first-pass perfusion MRI. However, both the static magnetic field (B-0) and radio frequency (RF) field (B-1) variations within the heart are comparatively higher at 3T than at 1.5T. The increased field variations can degrade the performance of a single rectangular saturation pulse that is conventionally used for magnetization preparation. The accuracy of T-1-weighted signal measurement depends on the uniformity of the magnetization saturation. The purpose of this study was to assess the relative effectiveness of the rectangular, pulse train, and adiabatic composite (BIR-4) saturation pulses in the human heart at 3T. In volunteers, after nominal saturation, the mean residual magnetization within the left ventricle (LV) was different between all three pulses (0.13 +/- 0.06 vs. 0.03 +/- 0.02 vs. 0.03 +/- 0.01, respectively; P < 0.001). Within paired groups, the mean residual magnetization was significantly higher for the rectangular pulse than for either the pulse train and BIR-4 pulses (P < 0.001), but not different between the pulse train and BIR-4 pulses. The performances of all three saturation pulses were comparatively poorer in the right ventricle (RV) than in the LV, respectively.